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Biomedical subjects

A G Parks

Publications and source records attributed to A G Parks.

At least 19 recordsLinked to original sources
PubMed1981

Electrophysiological study of motor nerve supply of pelvic floor.

Direct stimulation of a branch of the sacral nerves which lies above the pelvic floor and electromyographic recording of activity in the muscles of the pelvic floor showed that this nerve supplied the puborectalis muscle in 19 of the 20 nerves studied in 16 patients. Similar results were obtained when this nerve was stimulated in 2 patients undergoing anterior resection of the rectum. The pudendal nerve was also directly stimulated in 3 patients and found to supply only the ipsilateral external anal sphincter muscles. These findings suggest that the motor nerve supply of the important muscle of continence usually lies above the pelvic floor and not below it as previously believed.

Electromyography↗
PubMed1979

Pathogenesis of ano-rectal incontinence. A histometric study of the anal sphincter musculature.

Type 1 fibre predominance was found in the external anal sphincter, puborectalis and levator ani muscles of 17 control subjects, and of 16 patients with ano-rectal incontinence. In the external anal sphincter and puborectalis muscles of the control subjects the mean diameter of Type 2 fibres was slightly greater than that of Type 1 fibres, but in the levator ani muscles of control female subjects the mean diameter of Type 1 fibres was much greater than that of Type 2 fibres. In the patients with anorectal incontinence there was marked hypertrophy of fibres of both histochemical types. This was most marked in the puborectalis and external anal sphincter muscles. In 12 of the 16 incontinent patients there were histological and statistical features consistent with a neurogenic disorder. These histometric studies provide a quantitative basis for physiological and pathological studies of these muscles in incontinence and other anorectal disorders.

Adenosine Triphosphatases↗
PubMed1979

Responses of isolated human internal anal sphincter to drugs and electrical field stimulation.

The effects of drugs and electrical field stimulation on muscle strips from the human internal anal sphincter have been examined to provide information about the receptors and nerves that might be involved in the relaxation of the muscle in vivo. Acetylcholine and bethanechol usually relaxed muscle strips; this effect was abolished by hyoscine and antagonized to a varying degree by tetrodotoxin. Hexamethonium in concentrations sufficient to block relaxations to 1,1-dimethyl-4-phenylpiperazinium iodide or nicotine had no effect on relaxations due to acetylcholine, thereby indicating that acetylcholine was acting on muscarinic receptors. The nerves stimulated by acetylcholine released an unknown transmitter. Both 1,1-dimethyl-4-phenylpiperazinium iodide and nicotine relaxed muscle strips, possibly by releasing an adrenergic neurotransmitter which, because the responses to nicotinic receptor-stimulation were blocked by propranolol, stimulated beta-adrenergic inhibitory receptors. Sphincter muscle was also relaxed by electrical field stimulation of intrinsic nerves; this response was blocked by tetrodotoxin but unaffected by hexamethonium, hyposcine, or propranolol. The nerves responding to electrical field stimulation were therefore post-ganglionic, noncholinergic, and nonadrenergic. Compounds discounted as possible neurotransmitters of the noncholinergic, nonadrenergic inhibitory nerves were prostaglandin E2 and F2 alpha, histamine, 5-hydroxytryptamine, and dopamine. Some evidence allows vasoactive intestinal peptide and adenosine triphosphate to be considered as possible neurotransmitters; this could not be confirmed because selective antagonists are not yet available.

Adenosine Triphosphate↗
PubMed1978

Proctocolectomy without ileostomy for ulcerative colitis.

An operation has been developed that permits total removal of all disease-prone mucosa in ulcerative colitis but avoids the need for a permanent ileostomy. The colon and upper half of the rectum are excised and the remaining inflamed mucosa is stripped from the rectal stump down to the dentate line of the anal canal. A pouch is fashioned from a triplicated loop of terminal ileum. This is drawn down through the denuded rectum and an anastomosis created, via the per-anal approach, between the ileum just distal to the pouch and the mid-anal canal. A temporary ileostomy is made. Out of eight patients so treated, five were available for assessment, and four of them were highly satisfied with the result in improved health and function. The remaining three were awaiting closure of their ileostomies.

Adult↗
PubMed1978

A method of treating post-irradiation rectovaginal fistulas.

A sphincter-saving operative method of treating post-irradiation rectovaginal fistulas is presented. The technique involves the peranal anastomosis of healthy colon to the mid-anal canal using a 'sleeve' anastomosis. Four patients have been treated with cure of the fistula and a return to normal bowel habit. A fifth, with an irradiation ulcer causing intractable pain, also obtained complete relief of symptoms.

Aged↗
PubMed1977

Treatment of haemorrhoids in patients with inflammatory bowel disease.

A retrospective review of outcome was undertaken in forty-two patients with ulcerative colitis and twenty patients with Crohn's disease who were treated for haemorrhoids and the inflammatory bowel disease between 1935 and 1975. Both surgical and conservative treatment of haemorrhoids in patients with ulcerative colitis had low complication-rates (4 complications after 58 courses of treatment). In Crohn's disease the complication-rate was high (11 complications after 26 courses of treatment). One of the forty-two patients with ulcerative colitis and six of the twenty with Crohn's disease required rectal excision for complications apparently dating from the treatment of haemorrhoids. These results suggest that treatment of symptomatic haemorrhoids is usually safe in patients with ulcerative colitis but is contraindicated in those with Crohn's disease.

Adult↗
PubMed1977

Intersphincteric excision of the rectum.

Wide excision of the rectum in inflammatory bowel disease is both unnecessary and undesirable as the healthy pelvic floor is damaged and the pelvic nerves put at risk. An operative technique is described which includes dissection of the anal canal and rectum in the intersphincteric plane, i.e. the plane of fusion between the visceral rectum and anal canal and the somatic pelvic musculature, which minimizes these undesirable elements. Fifty-three cases are presented. Perineal wound healing rates are comparable with those of other methods of resection and only 1 of 14 men reported partial sexual dysfunction following this operation.

Adult↗
PubMed1977

Function of the anal sphincters following colo-anal anastomosis.

Developments in sphincter-saving operations for carcinoma of the rectum have led to renewed interest in the function of the pelvic floor muscles and the anal sphincters. Twelve patients with a colo-anal anastomosis have been investigated physiologically with reference to sphincter function. It has been shown that the rectum is not essential for the appreciation of impending evacuation, nor for the sphincter inhibitory reflexes, which in this study were elicited by balloon distension above the anastomosis.

Adult↗
PubMed1977

Giant condyloma of the rectum: report of a case.

The case of a woman who had a giant condyloma arising in the rectum and manifesting with a rectovaginal fistula is described. Radical surgical excision was performed. The clinical and pathologic features of this locally malignant condition are described and a plea is made for early radical surgical excision.

Abscess↗
PubMed1977

Sphincter denervation in anorectal incontinence and rectal prolapse.

Biopsies of the external anal sphincter, puborectalis, and levator ani muscles have been examined in 24 women and one man with long-standing anorectal incontinence, 18 of whom also had rectal prolapse, and in two men with rectal prolapse alone. In 16 of the women anorectal incontinence was of unknown cause, but in eight there was a history of difficult labour. Similar biopsies were examined in six control subjects. In all the incontinent patients there was histological evidence of denervation, which was most prominent in the external anal sphincter muscle biopsies, and least prominent in the levator ani muscles. Myopathic features, which were thought to be secondary, were present in the more abnormal biopsies. There were severe histological abnormalities in small nerves supplying the external anal sphincter muscle in the three cases in which material was available for study. We suggest that idiopathic anorectal incontinence may be the result of denervation of the muscles of the anorectal sling, and of the anal sphincter mechanism. This could result from entrapment or stretch injury of the pudendal or perineal nerves occurring as a consequence of rectal descent induced during repeated defaecation straining, or from injuries to these nerves associated with childbirth.

Adult↗
PubMed1976

A classification of fistula-in-ano.

A classification of anal fistulas is presented, which is the result of an analysis of 400 cases treated over the past 15 years, based on the pathogenesis of the disease and the normal muscular anatomy of the pelvic floor. Four main types were found but numerous variations of each occur, which are described. It is hoped that this will alert the surgeon to the various complex situations that he may encounter.

Abscess↗
PubMed1976

Fistula-in-Ano: perineal fistula of intra-abdominal or intrapelvic origin simulating fistula-in-ano--report of seven cases.

Fistulas manifesting in the perianal region but originating in the abdomen often have their true origin not recognized for extended periods. Examples of seven such complex cases are presented and discussed. Removal of the abdominal abnormality is mandatory before any cure can be effected; the perianal portion usually heals without any special local treatment.

Abscess↗